pgsql: Allow pg_{read,write}_all_data to access large objects.

Allow pg_{read,write}_all_data to access large objects.

Since the initial goal of pg_read_all_data was to be able to run
pg_dump as a non-superuser without explicitly granting access to
every object, it follows that it should allow reading all large
objects. For consistency, pg_write_all_data should allow writing
all large objects, too.

Author: Nitin Motiani <nitinmotiani(at)google(dot)com>
Co-authored-by: Nathan Bossart <nathandbossart(at)gmail(dot)com>
Reviewed-by: Dilip Kumar <dilipbalaut(at)gmail(dot)com>
Discussion: https://postgr.es/m/CAH5HC96dxAEvP78s1-JK_nDABH5c4w2MDfyx4vEWxBEfofGWsw%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/d98197602790e60ddb63e491cd9768ab9fc410ed

Modified Files
--------------
doc/src/sgml/user-manag.sgml | 4 +--
src/backend/catalog/aclchk.c | 18 ++++++++++++
src/test/regress/expected/privileges.out | 49 +++++++++++++++++++++++++++++++-
src/test/regress/sql/privileges.sql | 23 ++++++++++++++-
4 files changed, 90 insertions(+), 4 deletions(-)